I'm assuming that you want a hub motor, and you want to know if a 29" wheel will fit?
The answer is yes
you can buy a 29" hub motor and the wheel will fit fine as that is your wheel size (29" = 700c).
you can use the same tires you have now (35mm tires).
(29" generally refers to tires over 50mm, but the wheel diameter is the same)
Looks like you have quick release. hub motors have pretty big axles, so it is possible that it won't fit. Mine have a narrow (flat part) that I think is 10mm, and the bolt/nut diameter is 12mm. Steel is typically more forgiving than Aluminum, but you should be fine if you don't go too crazy with the power. I wouldn't put a front motor on your aluminum fork (Aluminum is easy to break, and if/when it does you are likely going to the hospital).
You have a 9 speed cassette, so you should get a motor that accepts a cassette - and disk brakes.
While it can be pretty straight forward to bolt on a kit, you'll need to understand the speed, range, and weight you want. Something like a 48v battery at 20 amps with a 15Amp Hour battery is probably typical, but you can go bigger or smaller from that. Battery is the biggest expense.